Computers crash and freeze. Your Windows PC may have automatically rebooted itself, too — if so, it probably experienced a blue screen of death when you weren’t looking. The first step in troubleshooting is finding more specific error details.
These will help you identify the problem. For example, the tools here may point the finger at a specific device driver. This could mean that the device driver itself is buggy, or that the underlying hardware is failing. Either way, it will give you a place to start searching.
So what to do if the computer frequently freezes or completely halts. An easy way to determine if your computer is in this situation is by pressing the Num Lock button on the keyboard and watching the Num Lock led to see if it turns off and on.
If you can get the light to turn off and on, press CTRL + ALT + DEL and End Task the frozen program. Otherwise, proceed through each of the follow sections in order.
Check the Reliability Monitor
The Reliability Monitor offers a quick, user-friendly interface that will display recent system and application crashes. It was added in Windows Vista, so it will be present on all modern versions of Windows. To open it, just tap the Windows key once and type “Reliability.” Click or press Enter to launch the “View reliability history” shortcut.
If Windows crashed or froze, you’ll see a “Windows failure” here. Application crashes will appear under “Application failures.” Other information here may actually be useful — for example, it shows when you installed various pieces of software. If the crashes started occuring after you installed a specific program or hardware driver, that piece of software could be the cause.
The Reliability Monitor is useful because it shows events from the Event Viewer in a more user-friendly way. If not for the Reliability Monitor, you’d have to get this information from the Windows Event Viewer itself.
To do so, launch the tool with a Start menu search for “Event Viewer,” select “System” under “Windows Logs,” and look for “Error” messages. These are the same error messages you can view in the Reliability Monitor. However, many other messages you don’t need to care about are also displayed here.
Software related issue
A computer locking up or freezing is often is caused by software related issues. If you are encountering lockups when the computer is opening a particular program, make sure you have all the latest updates for all running programs. You can find the latest updates for your software through the software developer or publisher.
Tip: If the computer has any malware, virus, or other malicious software it can also cause many problems. Make sure your computer is clean.
Too many programs open
Each program or window you open on your computer takes some of the computers resources to keep it running. If you have too many programs open at one time, your computer may be low on resources, and as a result, is freezing. Try only running one program at a time to make sure your freezing is not being caused by multiple programs running at the same time.
Driver related issue
A computer lock up can also be caused by outdated or corrupted drivers. For example, if there is an issue that exists with your video adapter drivers, your computer could lock up while playing a game or watching a movie.
First, make sure no errors exist in the Windows Device Manager by opening the Device Manager and verifying that no “Other Devices” are listed. You’ll also want to check the device list to see if any of them have a yellow exclamation mark or red X next to them. If they do, you’ll want to visit our page on identifying problems in Windows Device Manager.
Next, make sure you have the latest drivers for all major devices in your computer (video, sound, modem, and network). A listing of driver-related pages, as well as driver-related help, can be found on our drivers page.
Operating system related issue
Make sure your operating system has all of the latest updates installed on it.
View Blue Screen Crash Dump Details
Windows saves crash dumps from blue-screen errors to your system. For a more user-friendly way of examining these, we recommend NirSoft’s free BlueScreenView utility. (We don’t usually like recommending third-party software, but we do trust NirSoft.)
This tool will examine and memory dump files created during blue-screens and display a list of them. In particular, the important information here is the “Bug Check String” — the same message that’s displayed on your screen when the blue screen itself appears. Search for this message online and you’ll find information that can help you identify and solve your actual problem.
The list of drivers at the bottom of the window may also be helpful. For example, the blue-screens may consistently implicate a particular driver file, such as your graphics hardware driver. This may indicate there’s a problem with that specific driver. Or, that specific driver may be crashing because the underlying hardware itself is damaged. Either way, it can help point you in a more specific direction.
If you see a blue-screen while it happens, you can also just read the “Bug Check String” from it. On Windows 10 and Windows 8, Windows now displays a simple blue screen message with only a small note at the bottom of the screen with the message you might want to search. On Windows 7 and earlier versions of Windows, the bug check string appears near the top of the blue screen instead of at the bottom.
These blue-screen messages only stick around so long because Windows automatically reboots after a blue-screen. You could disable the auto-reboot feature to have Windows not reboot when it encounters a blue-screen. However, you can also just use the BlueScreenView utility to view the Bug Check String displayed on the blue screen after it happens.
Heat related issue
If the computer processor is getting too hot, it can cause the computer to freeze. If you have heard any abnormal noises coming from your computer recently, such as a high squealing, it could be an indication of a failing fan.
You can first start by verifying the fan on the power supply is working by examining the back of the computer and seeing if the fan is moving and moving smoothly. For the other fans in the computer, you have a few options. You can either open the computer and physically inspect them or, if the computer monitors the RPM of the fans, enter CMOS setup and make sure the BIOS does not report any errors.
Note: Laptop users may also want to try propping up their laptop on a book or notepad so that air can reach the bottom of the laptop to help verify if the laptop is having heat related issues.
Users may also be able to determine how hot their computer is by onboard thermal sensors. If your computer comes equipped with these sensors, make sure your CPU is not running too hot.
Caution: Some of the steps below require you open your computer. While working inside of a computer, be aware of ESD.
A hardware malfunction or misconfiguration can cause a computer to lock up. If you have recently added any new hardware into the computer, temporarily remove it to make sure it is not the cause of your issue.
Before attempting to remove any hardware, make sure the computer has no conflicts in Device Manager.
If you have not recently installed any new hardware, the next best solution is to remove certain components one by one. For example, you may remove your modem, network card, sound card, or any other expansion cards because they are not needed for the computer to operate. Run the computer without these cards to see if they are the cause of your issue. You should also try unplugging any peripheral (plugged in) devices one at a time to see if they’re causing your issues.
Serious issue with Windows
If you have tried all the above recommendations and the computer continues to lock up frequently, it’s possible that Windows may have been corrupted. Try running through the basic troubleshooting steps for your version of Windows on our basic troubleshooting page. If these additional steps do not resolve your issue, we suggest you backup all of your valuable information, and then erase and reinstall Windows.
If your computer turns off abnormally during or after the installation of your operating system, hardware components inside your computer may be malfunctioning. If so, the failing hardware is likely the RAM, CPU, Motherboard, or Power Supply (in that order).
If you access the same parts from another computer known to be working, try swapping the parts to isolate the faulty hardware. Otherwise, you need to have the computer serviced.
But Why Is it Crashing?
The above tools can help you get more of a handle on the actual problem. With a specific crash message from the blue screen message in hand, you can at least perform a web search to discover what might actually be the problem. It’s a much better starting point than looking for generic information about why a computer crashes or freezes.
If your computer just crashed or froze once, don’t sweat it. Nothing is completely perfect — a bug in Windows or a hardware driver could have caused the crash, and you may never see it again. You should worry when your computer is crashing regularly and consistently. Modern Windows PCs should not be blue-screening regularly at all — this should be an extremely rare occurrence.
If you’re encountering a lot of crashes, you may want to skip most of the troubleshooting process entirely and perform a “PC Reset” on Windows 10 or Windows 8. This will quickly set Windows back to its factory-default state, fixing any system corruption problems and removing any buggy drivers or malware that’s causing problems. You will have to reinstall your installed applications afterwards. On Windows 7, you’ll just have to reinstall Windows. If this doesn’t work, you’re probably experiencing a hardware problem. (But, bear in mind that if you install the same hardware drivers after resetting Windows and experience the problem again, it could be those drivers.)
The Memory Diagnostics tool built into Windows can also help. It will test your memory to ensure everything is working properly. If your memory is damaged, this can cause system instability and blue-screens.
Ultimately, it’s impossible to give advice that will solve every problem. The tools here will help you nail down your issue to a more specific error message or hardware driver and give you a way to start troubleshooting. But not every problem can be fixed with some software troubleshooting — your computer may have a hardware problem and there may be nothing you can do about it beyond replacing or fixing the hardware itself. As Windows becomes more stable, regular system freezes and blue-screens often point to underlying hardware problems.